Ghrelin is a hormone produced mainly by P/D1 cells lining the majority of the human stomach. These cells are distributed throughout the stomach and portions of the duodenum, but are highly concentrated in the area of the fundus and along the greater curvature of the stomach. Ghrelin, commonly called the hunger hormone, is associated with eating and fasting cycles in the body. It has been found that ghrelin levels increase before meals and decrease after meals. Further, it has been discovered that ghrelin levels in the plasma of obese individuals are typically lower than those in leaner individuals, while those suffering from the eating disorder anorexia nervosa typically have high plasma levels of ghrelin compared to both the constitutionally thin and normal-weight controls. These findings suggest that ghrelin plays a role in weight disorders.
Additionally, increased Ghrelin levels have been linked to enhanced learning and memory, a reduction in stress-induced depression, and shorter sleep durations.
Accordingly, there remains a need for methods and devices for regulating the activation of ghrelin hormones within a stomach in order to treat weight disorders, to promote learning and memory functions, to treat stress-induced depression, and to promote healthy sleep duration.